Method for producing semiconducting single-walled carbon nanotube dispersion

ABSTRACT

In one aspect, provided is a method for producing a semiconducting single-walled carbon nanotube dispersion. This method allows semiconducting single-walled carbon nanotubes to be separated from a single-walled carbon nanotube mixture containing semiconducting single-walled carbon nanotubes and metallic single-walled carbon nanotubes in an aqueous medium, and yet requires only an easily available separation agent and a simple operation. 
     One aspect of the present disclosure relates to a method for producing a semiconducting single-walled carbon nanotube dispersion. The method includes (A) preparing a single-walled carbon nanotube dispersion to be separated that contains single-walled carbon nanotubes composed of semiconducting single-walled carbon nanotubes and metallic single-walled carbon nanotubes, an aqueous medium, and a nonionic polymer containing a constitutional unit A derived from a monomer represented by the following formula (1), and (B) centrifuging the single-walled carbon nanotube dispersion to be separated and then collecting a supernatant containing the semiconducting single-walled carbon nanotubes from the centrifuged single-walled carbon nanotube dispersion. A content of the constitutional unit A in all constitutional units of the polymer is 2 mol % or more. The polymer is water soluble. 
       CH 2 ═CR 1 —COO—(EO) p (PO) q —R 2    (1)

TECHNICAL FIELD

The present disclosure relates to a method for producing asemiconducting single-walled carbon nanotube dispersion, a method forproducing semiconducting single-walled carbon nanotubes, which includesthe above production method as a process, and a method for separatingsemiconducting single-walled carbon nanotubes from metallicsingle-walled carbon nanotubes.

BACKGROUND ART

In recent years, nanometer-sized carbon materials are expected to beapplied in various fields due to their physical and chemical properties.Carbon nanotubes (also referred to as “CNTs” in the following) are oneof those materials. CNTs are composed of a sheet or sheets of graphenerolled into a cylindrical shape If the CNTs consist of a single layer,they are called single-walled carbon nanotubes (also referred to as“SWCNTs” in the following).

CNTs are known to have different electrical properties depending on howthe graphene sheet is rolled, the diameter, or the like. In particular,SWCNTs are significantly affected by the quantum effect, and thus canexhibit metallic behavior (metallic CNTs) or semiconducting behavior(semiconducting CNTs). SWCNTs may be produced by a known synthesismethod such as a high-pressure carbon monoxide disproportionation method(HiPco method), an enhanced direct injection pyrolytic synthesis method(e-DIPS method), an arc discharge method, or a laser ablation method.However, at present, a technology for producing either one of the twotypes of CNTs has not been established yet. When SWCNTs are used forvarious applications, only the desired type of SWCNTs needs to beseparated from the mixture of SWCNTs. The metallic CNTs have excellentelectrical conductivity and show potential for application in, e.g.,transparent electrodes for touch panels or solar cells and fine wiringof devices. The semiconducting CNTs show potential for application in, eg., transistors and sensors.

Several methods for separating semiconducting SWCNTs from metallicSWCNTs have been reported. For example, JP 2010-1162 A discloses adensity gradient centrifugation method in which SWCNTs are dispersedwith a surfactant such as sodium dodecyl sulfate or sodium cholate,mixed with a density gradient agent, and subjected to centrifugalseparation JP 2008-55375 A discloses an electric field separation methodin which SWCNTs are dispersed with a surfactant and separated under anapplied electric field. JP 2007-519594 A discloses a method in whichSWCNTs are mixed with a separation agent such as porphyrin in an organicsolvent to form a complex of semiconducting SWCNTs and the separationagent, and the complex is extracted. JP 2014-503445 A discloses a methodin which SWCNTs are mixed with a separation agent such as apolythiophene derivative in an organic solvent, and the interactionbetween semiconducting SWCNTs and the separation agent is used toselectively separate the semiconducting SWCNTs. JP WO 2014/136981 A1discloses a method in which SWCNTs are mixed with a separation agentsuch as a flavin derivative in an organic solvent, and the adsorption ofthe separation agent to semiconducting SWCNTs is used to separate thesemiconducting SWCNTs. JP 2012-36041 A discloses a method in whichSWCNTs are dispersed with a surfactant and placed in a separation vesselfilled with a separation material such as agar gel, and semiconductingSWCNTs that are adsorbed to the separation material are eluted from theseparation material by using an eluant.

DISCLOSURE OF INVENTION

One aspect of the present disclosure relates to a method for producing asemiconducting single-walled carbon nanotube dispersion (also referredto as a “semiconducting SWCNT dispersion” in the following). The methodincludes (A) preparing a single-walled carbon nanotube dispersion to beseparated (also referred to as a “SWCNT dispersion to be separated” inthe following) that contains single-walled carbon nanotubes composed ofsemiconducting single-walled carbon nanotubes (also referred to as“semiconducting SWCNTs” in the following) and metallic single-walledcarbon nanotubes (also referred to as “metallic SWCNTs” in thefollowing), an aqueous medium, and a nonionic polymer containing aconstitutional unit A derived from a monomer represented by thefollowing formula (1), and (B) centrifuging the SWCNT dispersion to beseparated and then collecting a supernatant containing thesemiconducting SWCNTs from the centrifuged SWCNT dispersion. A contentof the constitutional unit A in all constitutional units of the polymeris 2 mol % or more. The polymer is water soluble.

CH₂═CR¹—COO—(EO)_(p)(PO)_(q)—R²   (1)

where R¹ represents a hydrogen atom or a methyl group, R² represents ahydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, EOrepresents an ethyleneoxy group, PO represents a propyleneoxy group, prepresents an average number of moles of the ethyleneoxy group added andis 4 or more and 120 or less, and q represents an average number ofmoles of the propyleneoxy group added and is 0 or more and 50 or less.

One aspect of the present disclosure relates to a method for producingsemiconducting SWCNTs. The method includes filtering the semiconductingSWCNT dispersion obtained by the method for producing a semiconductingSWCNT dispersion of the present disclosure and collecting thesemiconducting SWCNTs.

One aspect of the present disclosure relates to a method for producingsemiconducting SWCNTs. The method includes drying the semiconductingSWCNT dispersion obtained by the method for producing a semiconductingSWCNT dispersion of the present disclosure to give a mixture containingthe semiconducting SWCNTs and the polymer, and removing the polymer fromthe mixture and collecting the semiconducting SWCNTs.

One aspect of the present disclosure relates to a method for producingsemiconducting SWCNTs. The method includes obtaining the semiconductingSWCNTs without performing a further separation treatment of thesemiconducting SWCNT dispersion obtained by the method for producing asemiconducting SWCNT dispersion of the present disclosure.

One aspect of the present disclosure relates to a method for separatingsemiconducting SWCNTs from metallic SWCNTs. The method includes (A)preparing a SWCNT dispersion to be separated that contains single-walledcarbon nanotubes composed of semiconducting SWCNTs and metallic SWCNTs,an aqueous medium, and a nonionic polymer containing a constitutionalunit A derived from a monomer represented by the following formula (1),and (B) centrifuging the SWCNT dispersion to be separated and thencollecting a supernatant containing the semiconducting SWCNTs from thecentrifuged SWCNT dispersion. A content of the constitutional unit A inall constitutional units of the polymer is 2 mol % or more. The polymeris water soluble.

CH₂═CR¹—COO—(EO)_(p)(PO)_(q)—R²   (1)

where R¹ represents a hydrogen atom or a methyl group, R² represents ahydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, EOrepresents an ethyleneoxy group, PO represents a propyleneoxy group, prepresents an average number of moles of the ethyleneoxy group added andis 4 or more and 120 or less, and q represents an average number ofmoles of the propyleneoxy group added and is 0 or more and 50 or less.

One aspect of the present disclosure relates to a method for producingan ink containing semiconducting SWCNTs. The method includes, as aprocess, the method for producing a semiconducting SWCNT dispersion ofthe present disclosure or the method for producing semiconducting SWCNTsof the present disclosure.

One aspect of the present disclosure relates to an ink containingsemiconducting SWCNTs. The ink contains semiconducting SWCNTs, at leastone selected from the group consisting of an organic solvent and water,and a nonionic polymer containing a constitutional unit A derived from amonomer represented by the following formula (1). A content of theconstitutional unit A in all constitutional units of the polymer is 2mol % or more. The polymer is water soluble.

CH₂═CR¹—COO—(EO)_(p)(PO)_(q)—R²   (1)

where R¹ represents a hydrogen atom or a methyl group, R² represents ahydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, EOrepresents an ethyleneoxy group, PO represents a propyleneoxy group, prepresents an average number of moles of the ethyleneoxy group added andis 4 or more and 120 or less, and q represents an average number ofmoles of the propyleneoxy group added and is 0 or more and 50 or less.

One aspect of the present disclosure relates to an aqueous dispersioncontaining semiconducting SWCNTs and a polymer containing aconstitutional unit A derived from a monomer represented by thefollowing formula (1). A content of the constitutional unit A in allconstitutional units of the polymer is 2 mol % or more.

CH₂═CR¹—COO—(EO)_(p)(PO)_(q)—R²   (1)

where R¹ represents a hydrogen atom or a methyl group, R² represents ahydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, EOrepresents an ethyleneoxy group, PO represents a propyleneoxy group, prepresents an average number of moles of the ethyleneoxy group added andis 4 or more and 120 or less, and q represents an average number ofmoles of the propyleneoxy group added and is 0 or more and 50 or less.

One aspect of the present disclosure relates to use of a polymer forseparation of semiconducting single-walled carbon nanotubes. The polymercontains a constitutional unit A derived from a monomer represented bythe following formula (1). A content of the constitutional unit A in allconstitutional units of the polymer is 2 mol % or more.

CH₂═CR¹—COO—(EO)_(p)(PO)_(q)—R²   (1)

where R¹ represents a hydrogen atom or a methyl group, R² represents ahydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms EOrepresents an ethyleneoxy group, PO represents a propyleneoxy group, prepresents an average number of moles of the ethyleneoxy group added andis 4 or more and 120 or less, and q represents an average number ofmoles of the propyleneoxy group added and is 0 or more and 50 or less.

DESCRIPTION OF THE INVENTION

The separation methods disclosed in JP 2010-1162 A and JP 2012-36041 Arequire the density gradient agent, the agar gel, or the like andinvolve many operation processes. The separation method disclosed in JP2008-55375 A requires an electrophoresis apparatus, takes time forseparation, and yields a low concentration of SWCNTs separated. Theseparation methods disclosed in JP 2007-519594 A JP 2014-503445 A, andJP WO 2014/136981 A1 are less practical because the separation has to beperformed in a nonpolar solvent, and expensive separation agents arerequired.

The present disclosure relates to a method for producing asemiconducting SWCNT dispersion. This method allows semiconductingSWCNTs to be separated from a SWCNT mixture containing semiconductingSWCNTs and metallic SWCNTs in an aqueous medium, and yet requires onlyan easily available separation agent and a simple operation. The presentdisclosure also relates to a method for producing semiconducting SWCNTs,which includes the above production method as a process. Moreover, thepresent disclosure relates to a method for separating semiconductingSWCNTs from metallic SWCNTs. Further, the present disclosure relates toa method for producing an ink containing semiconducting SWCNTs.

The present disclosure is based on the findings that the presence of aspecific nonionic polymer in the SWCNT dispersion to be separated makesit possible to separate semiconducting SWCNTs from metallic SWCNTs inthe SWCNT dispersion by means of an easily available separation agentand a simple operation

The present disclosure can provide a method for producing asemiconducting SWCNT dispersion, which uses an easily availableseparation agent and a simple operation to separate semiconductingSWCNTs from metallic SWCNTs in an aqueous medium and enables goodseparability of the semiconducting SWCNTs, a method for producingsemiconducting SWCNTs, which includes the above production method as aprocess, a method for separating semiconducting SWCNTs from metallicSWCNTs, and a method for producing an ink containing semiconductingSWCNTs.

The details of the mechanism of the effects of the present disclosureare still not clear, but may be assumed as follows.

In the present disclosure, the SWCNT dispersion to be separated containsthe nonionic polymer containing the constitutional unit A derived fromthe monomer represented by the formula (1). Since the constitutionalunit A has a high affinity for the aqueous medium, the polymer tends tobe easily dispersed in the dispersion. On the other hand, semiconductingSWCNTs and metallic SWCNTs differ from each other in the magnitude ofthe interaction between the polymer and the SWCNTs. Such a difference inthe magnitude of the interaction may cause a difference in the degree ofdispersion between semiconducting SWCNTs and metallic SWCNTs.Consequently, the semiconducting SWCNTs are selectively dispersed in thedispersion, while the metallic SWCNTs are aggregated. Therefore, it isconsidered that centrifugation of this dispersion may result in a goodseparation of the semiconducting SWCNTs and the metallic SWCNTs.

However, the present disclosure should not be interpreted solely by theabove mechanism.

[Method for Producing Semiconducting SWCNT Dispersion and Method forSeparating Semiconducting SWCNT from Metallic SWCNT]

In one aspect, the present disclosure relates to a method for producinga semiconducting SWCNT dispersion (also referred to as a “productionmethod of a dispersion of the present disclosure” in the following). Theproduction method of a dispersion of the present disclosure includes thefollowing process A and process B. In another aspect, the presentdisclosure relates to a method for separating semiconducting SWCNTs frommetallic SWCNTs (also referred to as a “separation method of the presentdisclosure” in the following). The separation method of the presentdisclosure includes the following process A and process B.

(Process A) Preparing a SWCNT dispersion to be separated that containssingle-walled carbon nanotubes composed of semiconducting SWCNTs andmetallic SWCNTs (also referred to as a “SWCNT mixture” in thefollowing), a nonionic polymer containing a constitutional unit Aderived from a monomer represented by the following formula (1) (alsoreferred to as a “monomer A” in the following), and an aqueous medium

(Process B) Centrifuging the SWCNT dispersion to be separated and thencollecting a supernatant containing the semiconducting SWCNTs from thecentrifuged SWCNT dispersion

CH₂═CR¹—COO—(EO)_(p)(PO)_(q)—R²   (1)

where R¹ represents a hydrogen atom or a methyl group, R² represents ahydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, EOrepresents an ethyleneoxy group, PO represents a propyleneoxy group, prepresents an average number of moles of the ethyleneoxy group added andis 4 or more and 120 or less, and q represents an average number ofmoles of the propyleneoxy group added and is 0 or more and 50 or less.

In the present disclosure, “collecting a supernatant containing thesemiconducting SWCNTs” means collecting the supernatant that has ahigher proportion of the semiconducting SWCNTs with respect to the ratioof the semiconducting SWCNTs to the metallic SWCNTs in the SWCNTdispersion to be separated, which has been prepared in the process A.This supernatant corresponds to the semiconducting SWCNT dispersion. Thepresent disclosure does not exclude the case where the supernatantcontains a relatively small amount of the metallic SWCNTs, compared tothe amount of the semiconducting SWCNTs. The improvement in separabilityof the semiconducting SWCNTs increases the proportion of thesemiconducting SWCNTs in the SWCNTs contained in the supernatant, andthus makes the semiconducting SWCNT dispersion more useful as a materialfor semiconductor devices.

In the process B, the supernatant may be collected, e.g., by separatingthe supernatant from the residue. The residue contains a precipitatethat contains a relatively large amount of the metallic SWCNTs, comparedto the amount of the semiconducting SWCNTs.

[Process A]

In the process A of the production method of a dispersion of the presentdisclosure and the separation method of the present disclosure, in oneor more embodiments, the SWCNT dispersion to be separated may beobtained by preparing a mixed solution (also referred to as a “mixedsolution A” in the following) that contains at least the polymercontaining the constitutional unit A derived from the monomer A, theSWCNT mixture, and the aqueous medium, and then subjecting the mixedsolution A to a dispersion treatment. The mixed solution A may beprepared, e.g., by adding the SWCNT mixture to an aqueous solution ofthe polymer.

[Nonionic Polymer Containing Constitutional Unit A Derived from MonomerA]

The polymer is water soluble from the viewpoint of improving theseparability of the semiconducting SWCNTs. In the present disclosure,the term “water soluble” means that at least 1 g of the polymer isdissolved in 100 g of water at 20° C. In one or more embodiments, thepolymer may be used to separate the semiconducting single-walled carbonnanotubes. In one aspect, the present disclosure relates the use of thepolymer for separation of the semiconducting single-walled carbonnanotubes. The polymer contains a constitutional unit A derived from amonomer represented by the following formula (1). The content of theconstitutional unit A in all the constitutional units of the polymer is2 mol % or more.

The constitutional unit A contained in the polymer is a constitutionalunit derived from the monomer A represented by the following formula(1). The constitutional unit A may be one type or a combination of twoor more types.

CH₂═CR³—COO—(EO)_(r)(PO)_(s)—R⁴   (2)

In the formula (1), R¹ represents a hydrogen atom or a methyl group andis preferably a methyl group from the viewpoint of improving theseparability of the semiconducting SWCNTs.

In the formula (1), R² represents a hydrogen atom or a hydrocarbon grouphaving 1 to 20 carbon atoms. When R² is a hydrocarbon group, the carbonnumber of R² is 1 or more and 20 or less, preferably 1 or more and 18 orless, more preferably 1 or more and 6 or less, even more preferably 1 ormore and 4 or less, and further preferably 1 from the viewpoint ofimproving the separability of the semiconducting SWCNTs and from theviewpoint of the availability of monomers. The hydrocarbon group of R²maybe, e.g., an alkyl group or a phenyl group.

Specifically, R² may be at least one selected from a stearyl group, alauryl group, a 2-ethylhexyl group, a butyl group, a phenyl group, anethyl group, a methyl group, and a hydrogen atom. R² is preferably amethyl group or a hydrogen atom from the viewpoint of improving theseparability of the semiconducting SWCNTs.

In the formula (1), p is 4 or more from the viewpoint of improving theseparability of the semiconducting SWCNTs and is 120 or less, preferably90 or less, more preferably 45 or less, even more preferably 25 or less,still more preferably 15 or less, and further preferably 10 or less fromthe viewpoint of improving the separability of the semiconducting SWCNTsand from the viewpoint of the availability of monomers.

In the formula (1), q is 0 or more and 50 or less, preferably 0 or moreand 30 or less, more preferably 0 or more and 10 or less, even morepreferably 0 or more and 3 or less, and further preferably 0 from theviewpoint of the water solubility of the polymer, from the viewpoint ofimproving the separability of the semiconducting SWCNTs, and from theviewpoint of the availability of monomers.

In the formula (1), q/(p+q) is preferably 0.7 or less, more preferably0.4 or less, and further preferably 0 from the viewpoint of the watersolubility of the polymer, from the viewpoint of improving theseparability of the semiconducting SWCNTs, and from the viewpoint of theavailability of monomers.

In the formula (1), there is no limitation to the order of addition ofthe ethyleneoxy group and the propyleneoxy group. When q is 2 or more,either a block bond or a random bond may be used.

The monomer A maybe, e.g., at least one selected from polyethyleneglycol monomethacrylate (PEGMA) and polyethylene glycol monoacrylate(PEGA).

The polymer may further contain a constitutional unit B derived from amonomer B other than the monomer A The constitutional unit B may be onetype or a combination of two or more types. The monomer B may be anynonionic monomer that is copolymerizable with the monomer A From theviewpoint of improving the separability of the semiconducting SWCNTs,the monomer B may be at least one monomer selected from a monomerrepresented by the following formula (2), a (meth)acrylic acid estermonomer, a (meth)acrylamide monomer, a styrene monomer, and a(meth)acrylonitrile monomer. In particular, the monomer represented bythe following formula (2) and the (meth)acrylic acid ester monomer arepreferred.

CH₂═CR¹—COO—(EO)_(p)(PO)_(q)—R²   (1)

In the formula (2), R³ represents a hydrogen atom or a methyl group, R⁴represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbonatoms, EO represents an ethyleneoxy group, PO represents a propyleneoxygroup, r represents an average number of moles of the ethyleneoxy groupadded and is 1 or more and less than 4, and s represents an averagenumber of moles of the propyleneoxy group added and is 0 or more and 50or less. There is no limitation to the order of addition of theethyleneoxy group and the propyleneoxy group. When r is 2 or more and sis 2 or more, either a block bond or a random bond may be used.

In the formula (2), R³ represents a hydrogen atom or a methyl group andis preferably a methyl group from the viewpoint of improving theseparability of the semiconducting SWCNTs.

In the formula (2), R⁴ represents a hydrogen atom or a hydrocarbon grouphaving 1 to 20 carbon atoms. When R⁴ is a hydrocarbon group, the carbonnumber of R⁴ is 1 or more and 20 or less, preferably 1 or more and 18 orless, more preferably 1 or more and 6 or less, even more preferably 1 ormore and 4 or less, and further preferably 1 from the viewpoint ofimproving the separability of the semiconducting SWCNTs and from theviewpoint of the availability of monomers. When R⁴ is a hydrocarbongroup, the hydrocarbon group may be, e.g., an alkyl group ora phenylgroup.

Specifically, R⁴ may be at least one selected from a stearyl group, alauryl group, a 2-ethylhexyl group, a butyl group, a phenyl group, anethyl group, a methyl group, and a hydrogen atom. R⁴ is preferably amethyl group or a hydrogen atom from the viewpoint of improving theseparability of the semiconducting SWCNTs.

In the formula (2), r is 1 or more and less than 4 from the viewpoint ofimproving the separability of the semiconducting SWCNTs.

In the formula (2), there is no limitation to the order of addition ofthe ethyleneoxy group and the propyleneoxy group. When r is 2 or moreand s is 2 or more, either a block bond or a random bond may be used.

In the formula (2), s is 0 or more and 50 or less, preferably 0 or moreand 30 or less, more preferably 0 or more and 10 or less, even morepreferably 0 or more and 3 or less, and further preferably 0 from theviewpoint of the water solubility of the polymer, from the viewpoint ofimproving the separability of the semiconducting SWCNTs, and from theviewpoint of the availability of monomers.

When the monomer B is the (meth)acrylic acid ester monomer, the monomerB may be, e.g., at least one selected from methyl (meth)acrylate, ethyl(meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate,stearyl (meth)acrylate, and benzyl (meth)acrylate. In particular, fromthe viewpoint of improving the separability of the semiconductingSWCNTs, the monomer B is preferably at least one selected from2-hydroxyethyl methacrylate (HEMA), lauryl methacrylate (LMA), andbenzyl methacrylate (BzMA).

When the monomer B is the (meth)acrylamide monomer, the monomer B maybe, e.g., at least one selected from acrylamide, methacrylamide,dimethylacrylamide, and dimethylmethacrylamide.

When the monomer B is the styrene monomer, the monomer B may be, e.g.,styrene or methyl styrene.

When the monomer B is the (meth)acrylonitrile monomer, the monomer Bmaybe, e.g., acrylonitrile or methacrylonitrile.

The polymer maybe, e.g., at least one selected from the following:polyethylene glycol (23) monomethacrylate polymer (PEG (23) MA);polyethylene glycol (9) monomethacrylate polymer (PEG (9) MA);polyethylene glycol (4) monomethacrylate polymer (PEG (4) MA);polyethylene glycol (23) monoacrylate/polyethylene glycol (2)monomethacrylate copolymer (PEG (23) MA/PEG (2) MA); polyethylene glycol(23) monoacrylate/2-hydroxyethyl methacrylate (PEG (23) MA/HEMA);polyethylene glycol (9) monoacrylate/lauryl methacrylate (PEG (9)MA/LMA); polyethylene glycol (9) monoacrylate/benzyl methacrylate (PEG(9) MA/BzMA); polyethylene glycol (23) monoacrylate/polyethylene glycol(23) monoacrylate copolymer (PEG (23) MA/PEG (23) A); and polyethyleneglycol (9) monoacrylate/polyethylene glycol (9) monoacrylate copolymer(PEG (9) MA/PEG (9) A). The numerical value in parentheses indicates theaverage number of moles added.

The content (mol %) of the constitutional unit A in all theconstitutional units of the polymer is 2 mol % or more, preferably 4 mol% or more, and more preferably 5 mol % or more from the viewpoint ofimproving the separability of the semiconducting SWCNTs. Furthermore,the content of the constitutional unit A is preferably 100 mol % or lessfrom the same viewpoint.

The content (mol %) of the constitutional unit A in all theconstitutional units of the polymer is preferably 100 mol % from theviewpoint of improving the separability of the semiconducting SWCNTs.

When the polymer contains the constitutional unit B, the content (mol %)of the constitutional unit A in all the constitutional units of thepolymer is preferably less than 100 mol %, more preferably 95 mol % orless, even more preferably 90 mol % or less, still more preferably 80mol % or less, yet more preferably 70 mol % or less, further preferably60 mol % or less, even further preferably 50 mol % or less, stillfurther preferably 40 mol % or less, yet further preferably 15 mol % orless, and yet further preferably 8 mol % or less.

The content (% by mass) of the constitutional unit Ain all theconstitutional units of the polymer is preferably 10% by mass or more,more preferably 20% by mass or more, and further preferably 30% by massor more from the viewpoint of improving the separability of thesemiconducting SWCNTs. Furthermore, the content of the constitutionalunit A is preferably 100% by mass or less from the same viewpoint.

When the polymer contains constitutional unit B, the content (% by mass)of the constitutional unit A in all the constitutional units of thepolymer is preferably less than 100% by mass, more preferably 98% bymass or less, and further preferably 96% by mass or less.

When the polymer contains the constitutional unit B, the content (mol %)of the constitutional unit B in all the constitutional units of thepolymer is preferably 98 mol % or less, more preferably 96 mol % orless, and further preferably 95 mol % or less from the viewpoint ofimproving the separability of the semiconducting SWCNTs. Furthermore,the content of the constitutional unit B is preferably more than 0 mol%, more preferably 5 mol % or more, and further preferably 10 mol % ormore from the same viewpoint.

When the polymer contains the constitutional unit B, the content (% bymass) of the constitutional unit B in all the constitutional units ofthe polymer is preferably 90% by mass or less, more preferably 80% bymass or less, and further preferably 70% by mass or less from theviewpoint of improving the separability of the semiconducting SWCNTs.Furthermore, the content of the constitutional unit B is preferably morethan 0% by mass, more preferably 2% by mass or more, and furtherpreferably 4% by mass or more from the same viewpoint.

The total content (% by mass) of the constitutional unit A and theconstitutional unit B in all the constitutional units of the polymer ispreferably 80% by mass or more, more preferably 90% by mass or more,even more preferably 95% by mass or more, and further preferably 100% bymass from the viewpoint of improving the separability of thesemiconducting SWCNTs.

When the polymer contains the constitutional unit B, the mass ratio(A/B) of the constitutional unit A to the constitutional unit B in thepolymer is preferably 0.05 or more, more preferably 0.11 or more, andfurther preferably 0.25 or more from the viewpoint of improving theseparability of the semiconducting SWCNTs. Furthermore, the mass ratio(A/B) is preferably 99 or less, more preferably 49 or less, and furtherpreferably 33 or less from the viewpoint of improving the separabilityof the semiconducting SWCNTs.

When the polymer contains the constitutional unit B, the molar ratio(A/B) of the constitutional unit A to the constitutional unit B in thepolymer is preferably 0.02 or more, more preferably 0.03 or more, andfurther preferably 0.04 or more from the viewpoint of improving theseparability of the semiconducting SWCNTs. Furthermore, the molar ratio(A B) is preferably 99 or less, more preferably 19 or less, and furtherpreferably 12 or less from the viewpoint of improving the separabilityof the semiconducting SWCNTs.

The weight average molecular weight of the polymer is preferably 2000 ormore, more preferably 5000 or more, even more preferably 7000 or more,and further preferably 8000 or more from the viewpoint of improving theseparability of the semiconducting SWCNTs. Furthermore, the weightaverage molecular weight of the polymer is preferably 250000 or less,more preferably 150000 or less, even more preferably 120000 or less, andfurther preferably 110000 or less from the same viewpoint. In thepresent disclosure, the weight average molecular weight of the polymeris determined by gel permeation chromatography and can be measuredspecifically by a method as described in Examples.

The number of ethyleneoxy groups derived from the constitutional unitAper constitutional unit of the polymer, which is the value obtained bymultiplying the average number of moles of EO added, represented by p inthe formula (1), by the mole fraction of the constitutional unit A ofthe polymer, is preferably 0.5 or more, more preferably 0.8 or more, andfurther preferably 1.0 or more from the viewpoint of improving theseparability of the semiconducting SWCNTs. Furthermore, the number ofethyleneoxy groups derived from the constitutional unit A is preferably120 or less, more preferably 90 or less, even more preferably 45 orless, still more preferably 25 or less, yet more preferably 12 or less,and further preferably 6 or less from the viewpoint of improving theseparability of the semiconducting SWCNTs. When the constitutional unitA is a combination of two or more types, the number of ethyleneoxygroups derived from the constitutional unit A can be calculated byadding together the values for each constitutional unit A Moreover, whenthe constitutional unit A is a combination of two or more types, thevalue obtained by multiplying the average number of moles of EO added(p) by the mole fraction of the constitutional unit A of the polymer canbe calculated by adding together the products of this multiplication foreach constitutional unit A

The molar ratio (α-methyl/α-hydrogen) of a methyl group in thea-position (also referred to as “α-methyl” in the following) to ahydrogen atom in the a-position (also referred to as “a-hydrogen” in thefollowing) of all the constitutional units of the polymer is preferably20/80 or more and 100/0 or less, more preferably 30/70 or more and 100/0or less, even more preferably 70/30 or more and 100/0 or less, stillmore preferably 80/20 or more and 100/0 or less, and further preferably90/10 or more and 100/0 or less from the viewpoint of improving theseparability of the semiconducting SWCNTs. The a-position is a locationrepresented by, e.g., R¹ of the formula (1) or R³ of the formula (2).

The mass ratio (polymer/SWCNTs) of the polymer to the SWCNTs in themixed solution A and in the SWCNT dispersion to be separated ispreferably 0.5 or more, more preferably 1 or more, even more preferably2 or more, and further preferably 5 or more from the viewpoint ofimproving the separability of the semiconducting SWCNTs. Furthermore,the mass ratio (polymer/SWCNTs) is preferably 100 or less, morepreferably 70 or less, even more preferably 50 or less, still morepreferably 30 or less, and further preferably 20 or less from the sameviewpoint.

The content of the polymer in the mixed solution A and in the SWCNTdispersion to be separated is preferably 0.05% by mass or more, morepreferably 0.1% by mass or more, even more preferably 0.2% by mass ormore, and further preferably 0.5% by mass or more from the viewpoint ofimproving the separability of the semiconducting SWCNTs. Furthermore,the content of the polymer is preferably 10% by mass or less, morepreferably 7% by mass or less, even more preferably 5% by mass or less,still more preferably 3% by mass or less, and further preferably 2% bymass or less from the same viewpoint.

[SWCNT]

Any SWCNTs may be used for the preparation of the mixed solution A andthe SWCNT dispersion to be separated. For example, the SWCNTs may besynthesized by a conventionally known synthesis method such as the HiPcomethod or the e-DIPS method, and may also differ in the way of rollingthe graphene sheet and the diameter. The SWCNTs may contain metallicSWCNTs and semiconducting SWCNTs in any ratio. Commonly synthesizedSWCNTs form a mixture of SWCNTs containing about ⅓ metallic SWCNTs andabout 213 semiconducting SWCNTs.

The average diameter of the SWCNTs is preferably 0.5 nm or more, andmore preferably 0.8 nm or more from the viewpoint of improving theseparability of the semiconducting SWCNTs. Furthermore, the averagediameter of the SWCNTs is preferably 3 nm or less, and more preferably 2nm or less from the same viewpoint. The average diameter of the SWCNTscan be calculated by measuring the diameters of 10 or more CNTs usingtransmission electron microscope images and taking the average of themeasured diameters.

The average length of the SWCNTs is preferably 0.1 μm or more, morepreferably 0.3 μm or more, and further preferably 0.5 μm or more fromthe viewpoint of electrical properties. Furthermore, the average lengthof the SWCNTs is preferably 100 μm or less, more preferably 50 μm orless, even more preferably 20 μm or less, and further preferably 10 μmor less from the viewpoint of improving the separability andproductivity of the semiconducting SWCNTs. The average length of theSWCNTs can be calculated by, e.g., measuring the lengths of 10 or moreCNTs using transmission electron microscope images and taking theaverage of the measured lengths.

The content of the SWCNTs in the mixed solution A and in the SWCNTdispersion to be separated is preferably 0.001% by mass or more, morepreferably 0.01% by mass or more, and further preferably 0.03% by massor more from the viewpoint of improving the separability of thesemiconducting SWCNTs. Furthermore, the content of the SWCNTs ispreferably 5% by mass or less, more preferably 1% by mass or less, andfurther preferably 0.5% by mass or less from the viewpoint of improvingthe separability and productivity of the semiconducting SWCNTs.

[Aqueous Medium]

The mixed solution A and the SWCNT dispersion to be separated contain anaqueous medium as a dispersion medium. The aqueous medium is preferablywater. The water is preferably pure water, ion-exchanged water, purifiedwater, or distilled water, and more preferably pure water from theviewpoint of improving the separability of the semiconducting SWCNTs.

The mixed solution A and the SWCNT dispersion to be separated maycontain a lower alcohol or a water-soluble organic solvent in additionto water as the aqueous medium. Examples of the lower alcohol includemethanol, ethanol, and isopropyl alcohol. Examples of the water-solubleorganic solvent include acetone, tetrahydrofuran, and dimethylformamide.

When the aqueous medium is a combination of water and a dispersionmedium other than water, the proportion of water in the aqueous mediumis preferably 70% by mass or more, more preferably 80% by mass or more,and further preferably 90% by mass or more from the viewpoint ofimproving the separability of the semiconducting SWCNTs.

The content of the aqueous medium in the mixed solution A and in theSWCNT dispersion to be separated is preferably 85% by mass or more, morepreferably 92% by mass or more, and further preferably 96% by mass ormore from the viewpoint of improving the separability and productivityof the semiconducting SWCNTs. Furthermore, the content of the aqueousmedium is preferably 99.9% by mass or less, more preferably 99.8% bymass or less, even more preferably 99.5% by mass or less, and furtherpreferably 99.0% by mass or less from the same viewpoint.

The dispersion treatment for the mixed solution A may be performed with,e.g., a disperser such as a bath-type ultrasonic disperser, a homomixer,a high-pressure homogenizer, an ultrasonic homogenizer, a jet mill, abead mill, or a MILLSER.

In the process A the mixed solution A may be defoamed before thedispersion treatment.

[Process B]

In the process B, the SWCNT dispersion to be separated that has beenprepared in the process A is subjected to centrifugation, and asupernatant containing the semiconducting SWCNTs is collected from thecentrifuged SWCNT dispersion. The supernatant has a higher proportion ofthe semiconducting SWCNTs with respect to the ratio of thesemiconducting SWCNTs to the metallic SWCNTs in the SWCNT dispersion tobe separated before the centrifugation. This proportion may varydepending on, e.g., the centrifugation conditions, and the rotationspeed of the centrifuge is preferably 5,000 rpm or more, and morepreferably 10,000 rpm or more from the viewpoint of improving theseparability and productivity of the semiconducting SWCNTs. Furthermore,the rotation speed of the centrifuge is preferably 100,000 rpm or less,and more preferably 70,000 rpm or less from the same viewpoint. Thegravitational acceleration of the centrifuge is preferably 10 kG ormore, and more preferably 50 kG or more from the viewpoint of improvingthe separability and productivity of the semiconducting SWCNTs.Furthermore, the gravitational acceleration of the centrifuge ispreferably 1000 kG or less, and more preferably 500 kG or less from thesame viewpoint.

The separability of the semiconducting SWCNTs in the supernatantobtained in the process B is preferably 1.1 or more, more preferably 1.3or more, even more preferably 1.4 or more, still more preferably 1.6 ormore, and further preferably 2.0 or more from the viewpoint ofsemiconductor characteristics. Furthermore, the separability of thesemiconducting SWCNTs is preferably 100 or less from the viewpoint ofyield. In the present disclosure, the separability of the semiconductingSWCNTs is a value determined by the following formula.

$\begin{matrix}{\frac{I_{S}\left( {{peak}{intensity}{of}{absorption}{wavelength}{specific}{to}{semi}{conducting}{}{SWCNTs}} \right)}{I_{M}\left( {{peak}{intensity}{of}{absorption}{wavelength}{specific}{to}{metallic}{SWCNTs}} \right)} = {{Separability}{of}{semiconducting}{SWCNTs}}} & \left\lbrack {{Numerical}{Expression}1} \right\rbrack\end{matrix}$

In one or more embodiments, the supernatant obtained in the process B isan aqueous dispersion containing the semiconducting SWCNTs and thepolymer. In other words, one aspect of the present disclosure relates toan aqueous dispersion containing the semiconducting SWCNTs and thepolymer that contains the constitutional unit A derived from the monomerA, in which the content of the constitutional unit A in all theconstitutional units of the polymer is 2 mol % or more.

[Method for Producing Semiconducting SWCNT, and Semiconducting SWCNT]

The semiconducting SWCNTs can be produced by collecting thesemiconducting SWCNTs from the semiconducting SWCNT dispersion that hasbeen obtained by the method for producing a semiconducting SWCNTdispersion of the present disclosure. The semiconducting SWCNTs may becollected from the semiconducting SWCNT dispersion by, e.g., filteringthe semiconducting SWCNT dispersion through a membrane filter toseparate out the semiconducting SWCNTs, and then drying thesemiconducting SWCNTs. When the semiconducting SWCNTs are filtered outfrom the semiconducting SWCNT dispersion, a pretreatment such asreprecipitation of the semiconducting SWCNTs in the semiconducting SWCNTdispersion may be performed before the filtration Alternatively, thesemiconducting SWCNTs may be collected from the semiconducting SWCNTdispersion by, e.g., drying the semiconducting SWCNT dispersion andremoving the coexisting polymer by means of cleaning, thermaldecomposition, or the like. Alternatively, the semiconducting SWCNTdispersion may be used as semiconducting SWCNTs without a furtherseparation treatment.

Thus, in one aspect, the present disclosure relates to a method forproducing semiconducting SWCNTs (also referred to as a “productionmethod A of semiconducting SWCNTs of the present disclosure” in thefollowing). The production method A of semiconducting SWCNTs of thepresent disclosure includes filtering the semiconducting SWCNTdispersion obtained by the method for producing a semiconducting SWCNTdispersion of the present disclosure and collecting the semiconductingSWCNTs.

In another aspect, the present disclosure relates to a method forproducing semiconducting SWCNTs (also referred to as a “productionmethod B of semiconducting SWCNTs of the present disclosure” in thefollowing). The production method B of semiconducting SWCNTs of thepresent disclosure includes drying the semiconducting SWCNT dispersionobtained by the method for producing a semiconducting SWCNT dispersionof the present disclosure to give a mixture containing thesemiconducting SWCNTs and the polymer, and removing the polymer from themixture and collecting the semiconducting SWCNTs.

In another aspect, the present disclosure relates to a method forproducing semiconducting SWCNTs (also referred to as a “productionmethod C of semiconducting SWCNTs of the present disclosure” in thefollowing). The production method C of semiconducting SWCNTs of thepresent disclosure includes obtaining the semiconducting SWCNTs withoutperforming a further separation treatment of the semiconducting SWCNTdispersion obtained by the method for producing a semiconducting SWCNTdispersion of the present disclosure.

In another aspect, the present disclosure relates to semiconductingSWCNTs (also referred to as “semiconducting SWCNTs of the presentdisclosure” in the following) obtained by the production method A or Bor C of semiconducting SWCNTs of the present disclosure.

[Method for Producing Ink Containing Semiconducting SWCNT]

In one aspect, the present disclosure relates to a method for producingan ink containing semiconducting SWCNTs (also referred to as a“production method of a semiconducting SWCNT containing ink of thepresent disclosure” in the following). The production method of asemiconducting SWCNT containing ink of the present disclosure includes,as a process, the method for producing a semiconducting SWCNT dispersionof the present disclosure or the method for producing semiconductingSWCNTs of the present disclosure. An embodiment of the production methodof a semiconducting SWCNT containing ink of the present disclosureincludes, e.g., the production method A or B or C of semiconductingSWCNTs of the present disclosure as a process, and further includesmixing the semiconducting SWCNTs and at least one of an organic solventand water, and optionally at least one of a surfactant and a resin.Another embodiment of the production method of a semiconducting SWCNTcontaining ink of the present disclosure includes, e.g., the method forproducing a semiconducting SWCNT dispersion of the present disclosure asa process, and also includes mixing the semiconducting SWCNT dispersionand optionally an organic solvent, a surfactant, and a resin that aremiscible with the dispersion.

Examples of the organic solvent include the following: aliphaticsolvents such as n-hexane, n-octane, and n-decane; alicyclic solventssuch as cyclohexane; aromatic solvents such as benzene and toluene;alcoholic solvents such as methanol and ethanol; and glycol ethersolvents such as diethylene glycol monomethyl ether, propylene glycolmonomethyl ether acetate, and butyl cellosolve. From the viewpoint ofimproving film forming properties, the ink containing semiconductingSWCNTs may further contain, e.g., polystyrene resin, acrylic resin, orvinyl resin as the resin that can be dissolved or dispersed in thesolvent, a surfactant known as a dispersant, and other additives. Thecontent of the semiconducting SWCNTs in the ink may be appropriately setin accordance with the intended use.

[Ink Containing Semiconducting SWCNT]

In one aspect, the present disclosure relates to an ink containingsemiconducting SWCNTs (also referred as a “semiconducting SWCNTcontaining ink of the present disclosure” in the following). Thesemiconducting SWCNT containing ink of the present disclosure containssemiconducting SWCNTs, at least one of an organic solvent and water, anda nonionic polymer containing a constitutional unit A derived from themonomer A The content of the constitutional unit A in all theconstitutional units of the polymer is 2 mol % or more, and the polymeris water soluble.

An embodiment of the semiconducting SWCNT containing ink of the presentdisclosure contains at least the semiconducting SWCNTs of the presentdisclosure, the nonionic polymer containing the constitutional unit Aderived from the monomer A and at least one of an organic solvent andwater, and optionally a surfactant and a resin. The content of theconstitutional unit A in all the constitutional units of the polymer is2 mol % or more, and the polymer is water soluble.

[Method for Producing Semiconductor Device]

One aspect of the present disclosure relates to a method for producing asemiconductor device. The method includes printing or applying thesemiconducting SWCNT containing ink obtained by the production method ofa semiconducting SWCNT containing ink of the present disclosure on asubstrate to form a semiconductor layer.

Another aspect of the present disclosure relates to a method forproducing a semiconductor device including a substrate, and a gateelectrode, a source electrode, and a drain electrode that are disposedon the substrate. The method includes printing or applying thesemiconducting SWCNT containing ink on the substrate to form asemiconductor circuit or a semiconductor film (semiconductor layer). Thesemiconducting SWCNT containing ink may be printed by, e.g., ink jetprinting, screen printing, offset printing, or letterpress printing. Themethod may also include forming a semiconductor film by printing orapplying the semiconducting SWCNT containing ink, and then optionallyetching the semiconductor film to form a circuit.

Regarding the above embodiments, the present invention further disclosesa method for producing a semiconducting single-walled carbon nanotubedispersion, a method for separating semiconducting single-walled carbonnanotubes from metallic single-walled carbon nanotubes, a method forproducing an ink containing semiconducting single-walled carbonnanotubes, and an ink containing semiconducting single-walled carbonnanotubes as follows.

<1>A method for producing a semiconducting single-walled carbon nanotubedispersion or a method for separating semiconducting single-walledcarbon nanotubes from metallic single-walled carbon nanotubes,comprising:

(A) preparing a single-walled carbon nanotube dispersion to be separatedthat contains single-walled carbon nanotubes composed of semiconductingsingle-walled carbon nanotubes and metallic single-walled carbonnanotubes, an aqueous medium, and a nonionic polymer containing aconstitutional unit A derived from a monomer represented by thefollowing formula (1); and

(B) centrifuging the single-walled carbon nanotube dispersion to beseparated and then collecting a supernatant containing thesemiconducting single-walled carbon nanotubes from the centrifugedsingle-walled carbon nanotube dispersion,

wherein a content of the constitutional unit A in all constitutionalunits of the polymer is 2 mol % or more, and the polymer is watersoluble:

CH₂═CR¹—COO—(EO)_(p)(PO)_(q)—R²   (1)

where R¹ represents a hydrogen atom or a methyl group, R² represents ahydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, EOrepresents an ethyleneoxy group, PO represents a propyleneoxy group, prepresents an average number of moles of the ethyleneoxy group added andis 4 or more and 120 or less, and q represents an average number ofmoles of the propyleneoxy group added and is 0 or more and 50 or less.

<2>The method for producing a semiconducting single-walled carbonnanotube dispersion or the method for separating semiconductingsingle-walled carbon nanotubes from metallic single-walled carbonnanotubes according to <1>, comprising:

(A) preparing a single-walled carbon nanotube dispersion to be separatedthat contains single-walled carbon nanotubes composed of semiconductingsingle-walled carbon nanotubes and metallic single-walled carbonnanotubes, an aqueous medium, and a nonionic polymer containing aconstitutional unit A derived from a monomer represented by thefollowing formula (1); and

(B) centrifuging the single-walled carbon nanotube dispersion to beseparated and then collecting a supernatant containing thesemiconducting single-walled carbon nanotubes from the centrifugedsingle-walled carbon nanotube dispersion,

wherein the content of the constitutional unit A in all theconstitutional units of the polymer is 100 mol %, and the polymer iswater soluble:

CH₂═CR¹—COO—(EO)_(p)(PO)_(q)—R²   (1)

where R¹ represents a hydrogen atom or a methyl group, R² represents astearyl group, a lauryl group, a 2-ethylhexyl group, a butyl group, aphenyl group, an ethyl group, a methyl group, or a hydrogen atom, EOrepresents an ethyleneoxy group, PO represents a propyleneoxy group, prepresents an average number of moles of the ethyleneoxy group added andis 4 or more and 45 or less, and q represents an average number of molesof the propyleneoxy group added and is 0 or more and 3 or less.

<3>The method for producing a semiconducting single-walled carbonnanotube dispersion or the method for separating semiconductingsingle-walled carbon nanotubes from metallic single-walled carbonnanotubes according to <1>, comprising:

(A) preparing a single-walled carbon nanotube dispersion to be separatedthat contains single-walled carbon nanotubes composed of semiconductingsingle-walled carbon nanotubes and metallic single-walled carbonnanotubes, an aqueous medium, and a nonionic polymer containing aconstitutional unit A derived from a monomer represented by thefollowing formula (1); and

(B) centrifuging the single-walled carbon nanotube dispersion to beseparated and then collecting a supernatant containing thesemiconducting single-walled carbon nanotubes from the centrifugedsingle-walled carbon nanotube dispersion,

wherein the content of the constitutional unit A in all theconstitutional units of the polymer is 100 mol %, and the polymer iswater soluble:

CH₂═CR¹—COO—(EO)_(p)(PO)_(q)—R²   (1)

where R¹ represents a hydrogen atom or a methyl group, R² represents ahydrogen atom or a methyl group, EO represents an ethyleneoxy group, POrepresents a propyleneoxy group, p represents an average number of molesof the ethyleneoxy group added and is 4 or more and 25 or less, and qrepresents an average number of moles of the propyleneoxy group addedand is 0.

<4>The method for producing a semiconducting single-walled carbonnanotube dispersion or the method for separating semiconductingsingle-walled carbon nanotubes from metallic single-walled carbonnanotubes according to <1>, comprising:

(A) preparing a single-walled carbon nanotube dispersion to be separatedthat contains single-walled carbon nanotubes composed of semiconductingsingle-walled carbon nanotubes and metallic single-walled carbonnanotubes, an aqueous medium, and a nonionic polymer containing aconstitutional unit A derived from a monomer represented by thefollowing formula (1); and

(B) centrifuging the single-walled carbon nanotube dispersion to beseparated and then collecting a supernatant containing thesemiconducting single-walled carbon nanotubes from the centrifugedsingle-walled carbon nanotube dispersion,

wherein the content of the constitutional unit A in all theconstitutional units of the polymer is 2 mol % or more and less than 100mol %, the polymer further contains a constitutional unit B derived fromat least one monomer selected from the group consisting of a monomerrepresented by the following formula (2), a (meth)acrylic acid estermonomer, a (meth)acrylamide monomer, a styrene monomer, and a(meth)acrylonitrile monomer, a content of the constitutional unit B inall the constitutional units of the polymer is more than 0 mol % and 98mol % or less, and the polymer is water soluble:

CH₂═CR¹—COO—(EO)_(p)(PO)_(q)—R²   (1)

where R¹ represents a hydrogen atom or a methyl group, R² represents ahydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms EOrepresents an ethyleneoxy group, PO represents a propyleneoxy group, prepresents an average number of moles of the ethyleneoxy group added andis 4 or more and 120 or less, and q represents an average number ofmoles of the propyleneoxy group added and is 0 or more and 50 or less,

CH₂═CR³—COO—(EO)_(r)(PO)_(s)—R⁴   (2)

where R³ represents a hydrogen atom or a methyl group, R⁴ represents ahydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, EOrepresents an ethyleneoxy group, PO represents a propyleneoxy group, rrepresents an average number of moles of the ethyleneoxy group added andis 1 or more and less than 4, and s represents an average number ofmoles of the propyleneoxy group added and is 0 or more and 50 or less.

<5>The method for producing a semiconducting single-walled carbonnanotube dispersion or the method for separating semiconductingsingle-walled carbon nanotubes from metallic single-walled carbonnanotubes according to <1>, comprising:

(A) preparing a single-walled carbon nanotube dispersion to be separatedthat contains single-walled carbon nanotubes composed of semiconductingsingle-walled carbon nanotubes and metallic single-walled carbonnanotubes, an aqueous medium, and a nonionic polymer containing aconstitutional unit A derived from a monomer represented by thefollowing formula (1); and

(B) centrifuging the single-walled carbon nanotube dispersion to beseparated and then collecting a supernatant containing thesemiconducting single-walled carbon nanotubes from the centrifugedsingle-walled carbon nanotube dispersion,

wherein the content of the constitutional unit A in all theconstitutional units of the polymer is 2 mol % or more and 95 mol % orless, the polymer further contains a constitutional unit B derived fromat least one monomer selected from the group consisting of a monomerrepresented by the following formula (2) and a (meth)acrylic acid estermonomer, a content of the constitutional unit B in all theconstitutional units of the polymer is 5 mol % or more and 98 mol % orless, and the polymer is water soluble:

CH₂═CR¹—COO—(EO)_(p)(PO)_(q)—R²   (1)

where R¹ represents a hydrogen atom or a methyl group, R² represents ahydrogen atom or a methyl group, EO represents an ethyleneoxy group, POrepresents a propyleneoxy group, p represents an average number of molesof the ethyleneoxy group added and is 4 or more and 25 or less, and qrepresents an average number of moles of the propyleneoxy group addedand is 0,

CH₂═CR³—COO—(EO)_(r)(PO)_(s)—R⁴   (2)

where R³ represents a hydrogen atom or a methyl group, R⁴ represents ahydrogen atom or a methyl group, EO represents an ethyleneoxy group, POrepresents a propyleneoxy group, r represents an average number of molesof the ethyleneoxy group added and is 1 or more and less than 4, and srepresents an average number of moles of the propyleneoxy group addedand iso.

<6>The method for producing a semiconducting single-walled carbonnanotube dispersion or the method for separating semiconductingsingle-walled carbon nanotubes from metallic single-walled carbonnanotubes according to <4>or <5>, wherein the total content of theconstitutional unit A and the constitutional unit B in all theconstitutional units of the polymer is 100% by mass.

<7>The method for producing a semiconducting single-walled carbonnanotube dispersion or the method for separating semiconductingsingle-walled carbon nanotubes from metallic single-walled carbonnanotubes according to any one of <1>to <6>, wherein a weight averagemolecular weight of the polymer is 5000 or more and 150000 or less.

<8>The method for producing a semiconducting single-walled carbonnanotube dispersion or the method for separating semiconductingsingle-walled carbon nanotubes from metallic single-walled carbonnanotubes according to any one of <1>to <7>, wherein the number ofethyleneoxy groups derived from the constitutional unit Aperconstitutional unit of the polymer is 0.8 or more and 25 or less.

<9>The method for producing a semiconducting single-walled carbonnanotube dispersion or the method for separating semiconductingsingle-walled carbon nanotubes from metallic single-walled carbonnanotubes according to any one of <1>to <8>, wherein a molar ratio(α-methyl/α-hydrogen) of a methyl group in an a-position to a hydrogenatom in an α-position of all the constitutional units of the polymer is20/80 or more and 100/0 or less.

<10>The method for producing a semiconducting single-walled carbonnanotube dispersion or the method for separating semiconductingsingle-walled carbon nanotubes from metallic single-walled carbonnanotubes according to any one of <1>to <9>, wherein a mass ratio(polymer/carbon nanotubes) of the polymer to the carbon nanotubes in thesingle-walled carbon nanotube dispersion to be separated is 5 or moreand 50 or less.

<11>The method for producing a semiconducting single-walled carbonnanotube dispersion or the method for separating semiconductingsingle-walled carbon nanotubes from metallic single-walled carbonnanotubes according to any one of <1>to <10>, wherein a content of thepolymer in the single-walled carbon nanotube dispersion to be separatedis 0.5% by mass or more and 5% by mass or less.

<12>The method for producing a semiconducting single-walled carbonnanotube dispersion or the method for separating semiconductingsingle-walled carbon nanotubes from metallic single-walled carbonnanotubes according to any one of <1>to <11>, wherein a content of thecarbon nanotubes in the single-walled carbon nanotube dispersion to beseparated is 0.03% by mass or more and 0.5% by mass or less.

<13>The method for producing a semiconducting single-walled carbonnanotube dispersion or the method for separating semiconductingsingle-walled carbon nanotubes from metallic single-walled carbonnanotubes according to any one of <1>to <12>, wherein an averagediameter of the single-walled carbon nanotubes used for preparing thesingle-walled carbon nanotube dispersion to be separated in the process(A) is 0.5 nm or more and 2 nm or less.

<14>A method for producing a semiconducting single-walled carbonnanotube dispersion, comprising:

(A) preparing a single-walled carbon nanotube dispersion to be separatedthat contains single-walled carbon nanotubes composed of semiconductingsingle-walled carbon nanotubes and metallic single-walled carbonnanotubes, an aqueous medium, and a nonionic polymer containing aconstitutional unit A derived from a monomer represented by the aboveformula (1); and

(B) centrifuging the single-walled carbon nanotube dispersion to beseparated and then collecting a supernatant containing thesemiconducting single-walled carbon nanotubes from the centrifugedsingle-walled carbon nanotube dispersion,

wherein an average diameter of the single-walled carbon nanotubes usedfor preparing the single-walled carbon nanotube dispersion to beseparated in the process (A) is 0.5 nm or more and 2 nm or less,

a content of the constitutional unit A in all constitutional units ofthe polymer is 2 mol % or more, and the polymer is water soluble, and

the number of ethyleneoxy groups derived from the constitutional unit Aper constitutional unit of the polymer is 0.5 or more and 120 or less.

<15>A method for producing semiconducting single-walled carbonnanotubes, comprising:

filtering the semiconducting single-walled carbon nanotube dispersionobtained by the method according to any one of <1>to <14>and collectingthe semiconducting single-walled carbon nanotubes.

<16>A method for producing semiconducting single-walled carbonnanotubes, comprising:

drying the semiconducting single-walled carbon nanotube dispersionobtained by the method according to any one of <1>to <14>to give amixture containing the semiconducting single-walled carbon nanotubes andthe polymer; and

removing the polymer from the mixture and collecting the semiconductingsingle-walled carbon nanotubes.

<17>A method for producing semiconducting single-walled carbonnanotubes, comprising:

obtaining the semiconducting single-walled carbon nanotubes withoutperforming a further separation treatment of the semiconductingsingle-walled carbon nanotube dispersion obtained by the methodaccording to any one of <1>to <14>.

<18>A method for producing an ink containing semiconductingsingle-walled carbon nanotubes, comprising:

the production method according to any one of <1>to <17>as a process.

<19>An ink containing semiconducting single-walled carbon nanotubes,comprising:

semiconducting single-walled carbon nanotubes;

at least one selected from the group consisting of an organic solventand water; and

a nonionic polymer as defined in any one of <1>to <9>,

wherein a content of the constitutional unit A in all constitutionalunits of the polymer is 2 mol % or more, and the polymer is watersoluble.

<20>An aqueous dispersion, comprising: semiconducting single-walledcarbon nanotubes; and

a polymer containing a constitutional unit A derived from a monomerrepresented by the above formula (1),

wherein a content of the constitutional unit Ain all constitutionalunits of the polymer is 2 mol % or more.

<21>Use of a polymer for separation of semiconducting single-walledcarbon nanotubes,

the polymer containing a constitutional unit A derived from a monomerrepresented by the above formula (1),

wherein a content of the constitutional unit Ain all constitutionalunits of the polymer is 2 mol % or more.

EXAMPLES

Hereinafter, the present disclosure will be described in more detail byway of examples. The following examples are illustrative only and thepresent disclosure is not limited to the examples.

1. Method for Measuring Various Parameters

[Measurement of Weight Average Molecular Eeight of Polymer]

The weight average molecular weight of the polymer used in thepreparation of the SWCNT dispersion to be separated was measured by gelpermeation chromatography (also referred to as “GPO” in the following)under the following conditions.

<GPC Conditions>

Measuring device: HLC-8320 GPC (manufactured by Tosoh Corporation)

Column: α−M+α−M (manufactured by Tosoh Corporation)

Eluant: N,N-dimethylformamide (DMF) solution of 60 mmol/L of H₃PO₄ and50 mmol/L of T

Flow rate: 1.0 mL/min

Column temperature: 40° C.

Detector: RI

Sample size: 0.5 mg/mL

Standard substance: monodisperse polystyrene (manufactured by TosohCorporation)

[Evaluation of Water Solubility]

1 g of polymer (or compound) was added to 100 g of water at 20° C.,stirred for 5 minutes, and visually observed to see whether insolublematter was present or not. The polymer was considered to be watersoluble if no insoluble matter was observed. In Tables 1 and 2, “A”indicates that the polymer was regarded as soluble in water and “B”indicates that the polymer was regarded as insoluble in water.

[Measurement of Average Diameter and Average Length of SWCNT]

The average diameter and average length of SWCNTs were calculated bymeasuring the diameters and lengths of 10 or more CNTs usingtransmission electron microscope images and taking the average of themeasured diameters and the average of the measured lengths,respectively.

2. Production of Polymers 1 to 16

[Polymer 1]

15 g of ethanol was charged in a reaction vessel equipped with anagitator, a reflux tube, a thermometer, a dropping funnel 1, and adropping funnel 2, and the reaction system was replaced with nitrogenwhile stirring. Then, the temperature was increased to 80° C. A solutionwas prepared for the dropping funnel 1, in which 50 g (100 mol %) ofmethoxy polyethylene glycol (23) methacrylate (“M⁻230G” manufactured bySHIN-NAKAMURA CHEMICAL Co., Ltd.) as a polymerization monomer and 0.15 g(3.0 mol % with respect to the monomer) of 3-mercapto-1,2-propanediol(manufactured by FUJIFILM Wako Pure Chemical Corporation) as a chaintransfer agent were dissolved in 23 g of ethanol. A solution wasprepared for the dropping funnel 2, in which 0.06 g (0.5 mol % withrespect to the monomer) of 2,2′-azobis(2,4-dimethylvaleronitrile)(“V-65B” manufactured by FUJIFILM Wako Pure Chemical Corporation) as apolymerization initiator was dissolved in 37 g of ethanol. Thesesolutions were simultaneously added dropwise to the reaction vesselthrough the respective dropping funnels 1, 2 over 1 hour. Aftercompletion of the dropping, the mixture was aged for 1 hour withstirring and the reaction was finished. Subsequently, ethanol wasdistilled off with a rotary evaporator, so that a polymer 1 wasproduced.

[Polymers 2 to 16]

Polymers 2 to 16 were produced in the same manner as the productionmethod of the polymer 1 except that the monomers, the amount of thechain transfer agent, and the amount of the polymerization initiatorwere changed as shown in Table 1.

Table 1 shows the physical properties of the polymers 1 to 16.

The monomers used in the production of the polymers 1 to 16 are asfollows.

(Monomer A)

PEG (23) MA: polyethylene glycol (23) monomethacrylate (“NK EsterM-230G” manufactured by SHIN-NAKAMURA CHEMICAL Co., Ltd.) (In theformula (1), R¹, R² are methyl, p is 23, and q is 0.)

PEG (9) MA: polyethylene glycol (9) monomethacrylate (“NK Ester M-90G”manufactured by SHIN-NAKAMURA CHEMICAL Co., Ltd.) (In the formula (1),R¹, R² are methyl, p is 9, and q is 0.)

PEG (4) MA: polyethylene glycol (4) monomethacrylate (“NK Ester M-40G”manufactured by SHIN-NAKAMURA CHEMICAL Co., Ltd.) (In the formula (1),R¹, R² are methyl, p is 4, and q is 0.)

PEG (23) A: polyethylene glycol (23) monoacrylate (“NK Ester AM-230G”manufactured by SHIN-NAKAMURA CHEMICAL Co., Ltd.) (In the formula (1),R¹ is hydrogen, R² is methyl, p is 23, and q is 0.)

PEG (9) A: polyethylene glycol (9) monoacrylate (“AM-90G” manufacturedby SHIN-NAKAMURA CHEMICAL Co., Ltd.) (In the formula (1), R¹ ishydrogen, R² is methyl, p is 9, and q is 0.)

(Monomer B)

PEG (2) MA: polyethylene glycol (2) monomethacrylate (“NK Ester M-20G”manufactured by SHIN-NAKAMURA CHEMICAL Co., Ltd.) (In the formula (2),R³, R⁴ are methyl, r is 2, and s is 0.)

HEMA: 2-hydroxyethyl methacrylate (manufactured by FUJIFILM Wako PureChemical Corporation)

LMA: lauryl methacrylate (manufactured by FUJIFILM Wako Pure ChemicalCorporation)

BzMA: benzyl methacrylate (manufactured by FUJIFILM Wako Pure ChemicalCorporation)

TABLE 1 Physical properties Number of EO derived Polymerization fromconditions consti- Chain Polymer- tutional transfer ization unit MonomerA Monomer B agent mol initiator mol A per mol % mol % mol % % (with %(with Weight consti- Water (% by (% by (% by respect to respect tomolecular tutional solu- Type mass) Type mass) Type mass) monomer)monomer) weight unit bility polymer 1 PEG(23)MA 100 (100) — — — — 3.00.5 34000 23 A polymer 2 PEG(23)MA 100 (100) — — — — 0.9 0.5 110000 23 Apolymer 3 PEG(9)MA 100 (100) — — — — 10 0.5 8000 9.0 A polymer 4PEG(9)MA 100 (100) — — — — 0.7 0.5 107000 9.0 A polymer 5 PEG(4)MA 100(100) — — — — 2.8 0.5 17000 4.0 A polymer 6 PEG(4)MA 100 (100) — — — —0.2 0.5 68000 4.0 A polymer 7 PEG(23)MA 10 (40) — — PEG(2)MA 90 (60) 0.90.5 62000 2.3 A polymer 8 PEG(23)MA 5 (30) — — HEMA 95 (70) 0.7 0.534000 1.1 A polymer 9 PEG(9)MA 90 (95) — — LMA 10 (5) 1.6 0.5 55000 8.1A polymer 10 PEG(9)MA 90 (96) — — BzMA 10 (4) 1.6 0.5 44000 8.1 Apolymer 11 PEG(23)MA 80 (80) PEG(23)A 20 (20) — — 3.0 0.5 55000 23.0 Apolymer 12 PEG(9)MA 30 (30) PEG(9)A 70 (70) — — 0.7 0.5 18000 9.0 Apolymer 13 — — — — PEG(2)MA 100 (100) 1.0 0.5 19000 — B polymer 14 — — —— HEMA 100 (100) 0.4 0.4 23000 — A

3. Preparation of Semiconducting SWCNT Dispersion

Examples 1 to 12, Comparative Examples 1 to 2

Each of the polymers shown in Table 2 was dissolved in ultrapure water(manufactured by Wako Pure Chemical Industries, Ltd.) to make a 1 mass %aqueous solution. Then, 30 mg of a SWCNT mixture synthesized by theHiPco method (“HiPco-Raw” manufactured by Nanolntegris Technologies,Inc., average diameter: 0.8 to 1.2 nm, average length: 0.4 to 0.7 μm)was added to 30 mL of the 1 mass % aqueous solution of the polymer toform a mixed solution.

Next, the mixed solution was dispersed with an ultrasonic homogenizer(“450D” manufactured by BRANSON) at an amplitude of 30% and atemperature of 10° C. for 10 minutes while stirring with a stirrer, thusproviding a SWCNT dispersion to be separated, as shown in Table 2. Thecontents of the SWCNT mixture and the polymer in the SWCNT dispersion tobe separated are shown in Table 2. The content of water is the remainderleft after subtracting the SWCNT mixture and the polymer from the SWCNTdispersion to be separated.

The SWCNT dispersion to be separated was centrifuged with anultracentrifuge (“CS100 GXII” rotor S50A manufactured by Hitachi KokiCo., Ltd.) at a rotation speed of 50000 rpm, a gravitationalacceleration of 210 kG, and a temperature of 20° C. for 60 minutes.Then, 80% by volume of the supernatant, as measured from the liquidlevel, was collected so as to prevent the settled sediment from rising.Thus, a semiconducting SWCNT dispersion was produced in Examples 1 to 12and Comparative Examples 1 to 2.

Comparative Examples 3, 4

A SWCNT dispersion to be separated and a supernatant (ie., asemiconducting SWCNT dispersion) in Comparative Example 3 were obtainedin the same manner as Example 1 except that the compound shown in Table2 was used instead of the polymer. The contents of the SWCNT mixture andthe compound in the SWCNT dispersion to be separated are shown in Table2. The content of water is the remainder left after subtracting theSWCNT mixture and the compound from the SWCNT dispersion to beseparated.

The compounds used in the preparation of the semiconducting SWCNTdispersions of Comparative Examples 3 to 4 are as follows.

Polyoxyethylene (100) stearyl ether (“Brij S100” manufactured bySigma-Aldrich)

Sodium dodecyl sulfate

4. Evaluation

[Evaluation of Separability]

Using an ultraviolet-visible-near infrared spectrophotometer capable ofmeasuring visible to infrared light (“UV-3600 Plug” manufactured byShimadzu Corporation), an absorbance was measured. The ratio of the peakintensity indicating semiconducting SWCNTs to the peak intensityindicating metallic SWCNTs was calculated and used as evaluationcriteria of the separability of the semiconducting SWCNTs from themetallic SWCNTs. The higher the calculated value, the higher theseparability of the semiconducting SWCNTs. Table 2 shows the results.

$\begin{matrix}{\frac{I_{S}\left( {{peak}{intensity}{of}{absorption}{wavelength}{specific}{to}{semiconducting}{SWCNTs}} \right)}{I_{M}\left( {{peak}{intensity}{of}{absorption}{wavelength}{specific}{to}{metallic}{SWCNTs}} \right)} = {{Separablity}{of}{semiconducting}{}{SWCNTs}}} & \left\lbrack {{Numerical}{Expression}2} \right\rbrack\end{matrix}$

The SWCNTs (HIPCO) used have an intrinsic wavelength of thesemiconducting SWCNTs at around 730 nm and an intrinsic wavelength ofthe metallic SWCNTs at around 480 nm.

TABLE 2 Composition of SWCNT dispersion to be separated Polymer orcompound Content of SWCNT constitutional mixture unit A in all Contentconstitutional Content Aqueous (% by units of polymer Water (% by mediumEvaluation mass) Type (mol %) solubility mass) Type Separability Ex. 10.1 polymer 1 100 A 1.0 water 1.27 Ex. 2 0.1 polymer 2 100 A 1.0 water1.35 Ex. 3 0.1 polymer 3 100 A 1.0 water 1.38 Ex. 4 0.1 polymer 4 100 A1.0 water 1.55 Ex. 5 0.1 polymer 5 100 A 1.0 water 1.74 Ex. 6 0.1polymer 6 100 A 1.0 water 1.79 Ex. 7 0.1 polymer 7 10 A 1.0 water 1.61Ex. 8 0.1 polymer 8 5 A 1.0 water 2.2 Ex. 9 0.1 polymer 9 90 A 1.0 water1.53 Ex. 10 0.1 polymer 10 90 A 1.0 water 1.43 Ex. 11 0.1 polymer 11 100A 1.0 water 1.22 Ex. 12 0.1 polymer 12 100 A 1.0 water 1.41 Comp. Ex. 10.1 polymer 13 0 B 1.0 water Not dispersed Comp. Ex. 2 0.1 polymer 14 0A 1.0 water Not dispersed Comp. Ex. 3 0.1 polyoxyethylene (100) stearylether A 1.0 water 0.9 Comp. Ex. 4 0.1 sodium dodecyl sulfate A 1.0 water0.9

As shown in Table 2, the separated SWCNT dispersions in Examples 1 to 12are superior to the separated SWCNT dispersions in Comparative Examples1 to 4 in the separability of the semiconducting SWCNTs.

INDUSTRIAL APPLICABILITY

As described above, the method for producing a semiconducting SWCNTdispersion of the present disclosure allows semiconducting SWCNTs to beseparated from metallic SWCNTs in an aqueous medium without the use ofe.g., a density gradient agent, and yet requires only an easilyavailable separation agent and a simple operation. Thus, the presentdisclose can improve the production efficiency not only in the methodfor producing a semiconducting SWCNT dispersion, but also in the methodfor producing semiconducting SWCNTs themselves.

1. A method for producing a semiconducting single-walled carbon nanotubedispersion, comprising: (A) preparing a single-walled carbon nanotubedispersion to be separated that contains single-walled carbon nanotubescomposed of semiconducting single-walled carbon nanotubes and metallicsingle-walled carbon nanotubes, an aqueous medium, and a nonionicpolymer containing a constitutional unit A derived from a monomerrepresented by the following formula (1); and (B) centrifuging thesingle-walled carbon nanotube dispersion to be separated and thencollecting a supernatant containing the semiconducting single-walledcarbon nanotubes from the centrifuged single-walled carbon nanotubedispersion, wherein a content of the constitutional unit A in allconstitutional units of the polymer is 2 mol % or more, and the polymeris water soluble:CH₂═CR¹—COO—(EO)_(p)(PO)_(q)—R²   (1) where R¹ represents a hydrogenatom or a methyl group, R² represents a hydrogen atom or a hydrocarbongroup having 1 to 20 carbon atoms, EO represents an ethyleneoxy group,PO represents a propyleneoxy group, p represents an average number ofmoles of the ethyleneoxy group added and is 4 or more and 120 or less,and q represents an average number of moles of the propyleneoxy groupadded and is 0 or more and 50 or less.
 2. The method for producing asemiconducting single-walled carbon nanotube dispersion according toclaim 1, wherein the number of ethyleneoxy groups derived from theconstitutional unit A per constitutional unit of the polymer is 0.5 ormore and 120 or less.
 3. The method for producing a semiconductingsingle-walled carbon nanotube dispersion according to claim 1, whereinthe content of the constitutional unit A in all the constitutional unitsof the polymer is 100 mol %.
 4. The method for producing asemiconducting single-walled carbon nanotube dispersion according toclaim 1, wherein the polymer further contains a constitutional unit Bderived from at least one monomer B selected from the group consistingof a monomer represented by the following formula (2), a (meth)acrylicacid ester monomer, a (meth)acrylamide monomer, a styrene monomer, and a(meth)acrylonitrile monomer:CH₂═CR³—COO—(EO)_(r)(PO)_(s)—R²   (1) where R³ represents a hydrogenatom or a methyl group, R⁴ represents a hydrogen atom or a hydrocarbongroup having 1 to 20 carbon atoms, EO represents an ethyleneoxy group,PO represents a propyleneoxy group, r represents an average number ofmoles of the ethyleneoxy group added and is 1 or more and less than 4,and s represents an average number of moles of the propyleneoxy groupadded and is 0 or more and 50 or less.
 5. The method for producing asemiconducting single-walled carbon nanotube dispersion according toclaim 4, wherein a content of the constitutional unit B in all theconstitutional units of the polymer is more than 0 mol % and 98 mol % orless.
 6. The method for producing a semiconducting single-walled carbonnanotube dispersion according to claim 1, wherein an average diameter ofthe single-walled carbon nanotubes used for preparing the single-walledcarbon nanotube dispersion to be separated in the process (A) is 0.5 nmor more and 2 nm or less.
 7. The method for producing a semiconductingsingle-walled carbon nanotube dispersion according to claim 1, whereinseparability of the semiconducting single-walled carbon nanotubes in thesupernatant obtained in the process (B) is 1.1 or more, and theseparability of the semiconducting single-walled carbon nanotubes(semiconducting SWCNTs) is a value determined the following formula$\frac{I_{S}\left( {{peak}{intensity}{of}{absorption}{wavelength}{specific}{to}{semiconducting}{SWCNTs}} \right)}{I_{M}\left( {{peak}{intensity}{of}{absorption}{wavelength}{specific}{to}{metallic}{SWCNTs}} \right)} = {{Separablity}{of}{semiconducting}{}{{SWCNTs}.}}$8. (canceled)
 9. A method for producing semiconducting single-walledcarbon nanotubes, comprising: filtering the semiconducting single-walledcarbon nanotube dispersion obtained by the method according to claim 1and collecting the semiconducting single-walled carbon nanotubes.
 10. Amethod for producing semiconducting single-walled carbon nanotubes,comprising: drying the semiconducting single-walled carbon nanotubedispersion obtained by the method according to claim 1 to give a mixturecontaining the semiconducting single-walled carbon nanotubes and thepolymer; and removing the polymer from the mixture and collecting thesemiconducting single-walled carbon nanotubes.
 11. A method forproducing semiconducting single-walled carbon nanotubes, comprising:obtaining the semiconducting single-walled carbon nanotubes withoutperforming a further separation treatment of the semiconductingsingle-walled carbon nanotube dispersion obtained by the methodaccording to claim
 1. 12. A method for separating semiconductingsingle-walled carbon nanotubes from metallic single-walled carbonnanotubes, comprising: (A) preparing a single-walled carbon nanotubedispersion to be separated that contains single-walled carbon nanotubescomposed of semiconducting single-walled carbon nanotubes and metallicsingle-walled carbon nanotubes, an aqueous medium, and a nonionicpolymer containing a constitutional unit A derived from a monomerrepresented by the following formula (1); and (B) centrifuging thesingle-walled carbon nanotube dispersion to be separated and thencollecting a supernatant containing the semiconducting single-walledcarbon nanotubes from the centrifuged single-walled carbon nanotubedispersion, wherein a content of the constitutional unit A in allconstitutional units of the polymer is 2 mol % or more, and the polymeris water soluble:CH₂═CR³—COO—(EO)_(r)(PO)_(s)—R²   (1) where R^(l) represents a hydrogenatom or a methyl group, R² represents a hydrogen atom or a hydrocarbongroup having 1 to 20 carbon atoms, EO represents an ethyleneoxy group,PO represents a propyleneoxy group, p represents an average number ofmoles of the ethyleneoxy group added and is 4 or more and 120 or less,and q represents an average number of moles of the propyleneoxy groupadded and is 0 or more and 50 or less.
 13. A method for producing an inkcontaining semiconducting single-walled carbon nanotubes, comprising:the production method according to claim 1 as a process.
 14. (canceled)15. An aqueous dispersion comprising: semiconducting single-walledcarbon nanotubes; and a polymer containing a constitutional unit Aderived from a monomer represented by the following formula (1), whereina content of the constitutional unit A in all constitutional units ofthe polymer is 2 mol % or more,CH₂═CR³—COO—(EO)_(r)(PO)_(s)—R²   (1) where R¹ represents a hydrogenatom or a methyl group, R² represents a hydrogen atom or a hydrocarbongroup having 1 to 20 carbon atoms, EO represents an ethyleneoxy group,PO represents a propyleneoxy group, p represents an average number ofmoles of the ethyleneoxy group added and is 4 or more and 120 or less,and q represents an average number of moles of the propyleneoxy groupadded and is 0 or more and 50 or less.
 16. (canceled)
 17. The method forproducing a semiconducting single-walled carbon nanotube dispersionaccording to claim 1, wherein p is 4 or more and 25 or less in theformula (1).
 18. The method for producing a semiconducting single-walledcarbon nanotube dispersion according to claim 1, wherein q is 0 or moreand 3 or less in the formula (1).
 19. The method for producing asemiconducting single-walled carbon nanotube dispersion according toclaim 1, wherein the content (mol %) of the constitutional unit A in allthe constitutional units of the polymer is 5 mol % or more and 100 mol %or less.
 20. The method for producing a semiconducting single-walledcarbon nanotube dispersion according to claim 4, wherein a content (mol%) of the constitutional unit B in all the constitutional units of thepolymer is 5 mol % or more and 95 mol % or less.
 21. The method forproducing a semiconducting single-walled carbon nanotube dispersionaccording to claim 4, wherein the monomer B is at least one selectedfrom the group consisting of 2-hydroxyethyl methacrylate (HEMA), laurylmethacrylate (LMA), and benzyl methacrylate (BzMA).
 22. The method forproducing a semiconducting single-walled carbon nanotube dispersionaccording to claim 1, wherein a mass ratio (polymer/SWCNTs) of thepolymer to the single-walled carbon nanotubes (SWCNTs) in thesingle-walled carbon nanotube dispersion to be separated is 0.5 or moreand 20 or less.